KR102382128B1 - Oxide sintered body, sputtering target and oxide semiconductor film - Google Patents

Abstract

An oxide sintered body comprising an oxide containing an In element, a Zn element, a Sn element, and a Y element, the sintered compact having a density of 100.00% or more of the theoretical density.

Description

Oxide sintered body, sputtering target and oxide semiconductor film

The present invention relates to a thin film transistor (TFT) used in a display device such as a liquid crystal display (LCD) or an organic electroluminescence (EL) display, an oxide semiconductor film that can be used in a TFT, and an oxide semiconductor film, etc. It is related with the sputtering target which can be used, and the oxide sintered compact used as the material.

The amorphous (amorphous) oxide semiconductor used for thin film transistors has a high carrier mobility compared to general-purpose amorphous silicon (a-Si), has a large optical band gap, and can be formed at a low temperature, so it has a large size and high resolution. Applications are expected for next-generation displays that require high-speed operation and resin substrates with low heat resistance.

In formation of the said oxide semiconductor (film), the sputtering method of sputtering a sputtering target is used preferably. The reason is that the thin film formed by the sputtering method is superior to the thin film formed by the ion plating method, the vacuum vapor deposition method, or the electron beam vapor deposition method in the film surface direction (in the film surface) in terms of in-plane uniformity such as the component composition and the film thickness. This is because a thin film having the same component composition as that of the target can be formed.

Patent Document 1 describes the use of an oxide sintered body composed of In, Y and O, Y/(Y+In) of 2.0 to 40 atomic%, and a volume resistivity of 5×10 ⁻² Ωcm or less as a target. As for content of Sn element, there exists description that Sn/(In+Sn+ all other metal atoms) is 2.8-20 atomic%.

Patent Document 2 describes an oxide sintered body composed of In, Sn, Y and O and Y/(In+Sn+Y) of 0.1 to 2.0 atomic%, and a sputtering target using the same. It is described that the thin film obtained from this target comprises apparatuses, such as a flat panel display and a touch panel.

Patent Document 3 describes a sintered body having a lattice constant intermediate the lattice constants of YInO ₃ and In ₂ O ₃ , and using this as a sputtering target. Further, a sintered body containing a compound of In ₂ O ₃ and Y ₂ SnO ₇ as a composition comprising indium oxide, yttrium oxide and tin oxide is described. Further, a sintered body made of yttrium oxide, tin oxide, and zinc oxide and containing Y ₂ Sn ₂ O ₇ and ZnO or Zn ₂ SnO ₄ compound is described. This sintered compact is fired under special conditions of oxygen atmosphere using an atmospheric sintering furnace, and although the volume resistivity is low and the density is high, it is brittle and may crack or chip during the production of sputtering. there was Moreover, since the strength is low, it may be cracked when sputtering with a large power.

Patent Document 4 discloses an oxide sintered body containing In, Sn and Zn and at least one element selected from the group consisting of Mg, Si, Al, Sc, Ti, Y, Zr, Hf, Ta, La, Nd and Sm; and using it as a sputtering target. This sintered compact is a sintered compact containing _{In2O3 and a Zn2SnO4} compound.

In Patent Document 5, an element selected from In, Sn, Zn and Mg, Al, Ga, Si, Ti, Y, Zr, Hf, Ta, La, Nd and Sm is added, a bixbite structure compound and a spinel structure A sputtering target containing the compound is described.

In Patent Document 6, elements selected from In, Sn, Zn and Hf, Zr, Ti, Y, Nb, Ta, W, Mo and Sm are added, In ₂ O ₃ phase, spinel phase, X ₂ Sn ₂ O A sintered body comprising ₇ phases (pyrochlor phase) and at least one layer selected from ZnX ₂ O ₆ is described.

On the other hand, the demand for a TFT with better high performance is high, and there is a great demand for a material having high mobility and having little change in properties during heating or the like when a protective film or an insulating film is formed by chemical vapor deposition (CVD).

Japanese Patent Laid-Open No. 09-209134 Japanese Patent Laid-Open No. 2000-169219 International Publication No. 2010/032432 International Publication No. 2012/153507 Japanese Patent Laid-Open No. 2014-111818 Japanese Patent Laid-Open No. 2015-214436

When an element with a large atomic radius such as yttrium is added to an indium oxide-based target material, the lattice constant of indium oxide changes, the sintering density does not rise, and the strength of the target material decreases, or during sputtering with large power. Thermal stress may cause microcracks or chipping to cause abnormal discharge in some cases. These phenomena generate defects, resulting in deterioration of TFT performance.

An object of the present invention is to provide a TFT exhibiting excellent TFT performance, an oxide semiconductor film usable for the TFT, a sputtering target capable of forming the oxide semiconductor film, and an oxide sintered body that is a material thereof.

According to the present invention, the following oxide sintered body and the like are provided.

1. Containing an oxide containing element In, element Zn, element Sn and element Y;

The oxide sintered compact characterized in that the density of the sintered compact is 100.00% or more of the theoretical density.

_{2. The} oxide sintered body of ₁ characterized by containing the bixbite phase represented by In2O3, and _the pyrochlore phase represented by _Y2Sn2O7 .

3. The oxide sintered body according to 2, wherein at least one of the Y element and the Zn element is solid-solution substituted on the bixbite.

4. The oxide sintered body according to any one of 1 to 3, wherein the atomic ratio of the Zn element, Y element, Sn element, and In element is in the following range.

0.01≤Zn/(In+Zn+Y+Sn)≤0.25

0.03≤Y/(In+Zn+Y+Sn)≤0.25

0.03≤Sn/(In+Zn+Y+Sn)≤0.30

0.20≤In/(In+Zn+Y+Sn)≤0.93

5. An oxide sintered body comprising element In, Zn element, Sn element and Y element, wherein the atomic ratio of the Zn element and In element is in the following range, and does not contain a spinel phase represented by Zn ₂ SnO ₄ .

0.01≤Zn/(In+Zn+Y+Sn)≤0.25

0.50≤In/(In+Zn+Y+Sn)

6. The oxide sintered body according to 5 characterized by containing a bixbite phase represented by In ₂ O ₃ and a pyrochlor phase represented by Y ₂ Sn ₂ O ₇ .

7. The oxide sintered body according to 6, wherein at least one of the Y element and the Zn element is substituted by solid solution on the bixbite.

8. The oxide sintered body according to any one of 5 to 7, wherein the atomic ratio of the Y element and the Sn element is in the following range.

0.03≤Y/(In+Zn+Y+Sn)≤0.25

0.03≤Sn/(In+Zn+Y+Sn)≤0.30

9. It contains In element, Zn element, Sn element and Y element, and the atomic ratio of the Zn element and In element is within the following range;

It consists only of a bixbite phase represented by In ₂ O ₃ and a pyrochlor phase represented by Y ₂ Sn ₂ O ₇ , or

An oxide sintered body comprising only a bixbite phase represented by In ₂ O ₃ , a pyrochlor phase represented by Y ₂ Sn ₂ O ₇ , and an indium trizine coindate phase represented by In((Zn ₃ In)O ₆ ) .

0.01≤Zn/(In+Zn+Y+Sn)≤0.25

0.50≤In/(In+Zn+Y+Sn)

10. The oxide sintered body according to 9, wherein at least one of the Y element and the Zn element is substituted by solid solution on the bixbite.

11. The oxide sintered body according to 9 or 10, wherein the atomic ratio of the Y element and the Sn element is in the following range.

0.03≤Y/(In+Zn+Y+Sn)≤0.25

0.03≤Sn/(In+Zn+Y+Sn)≤0.30

12. The oxide sintered compact in any one of 1-11 is contained, The sputtering target characterized by the above-mentioned.

13. An oxide semiconductor film characterized in that the atomic ratio of Zn element, Y element, Sn element and In element is within the following range.

0.01≤Zn/(In+Zn+Y+Sn)≤0.25

0.03≤Y/(In+Zn+Y+Sn)≤0.25

0.03≤Sn/(In+Zn+Y+Sn)≤0.30

0.20≤In/(In+Zn+Y+Sn)≤0.93

14. The oxide semiconductor film according to 13, characterized in that it is amorphous.

15. A thin film transistor comprising the oxide semiconductor film according to 13 or 14.

ADVANTAGE OF THE INVENTION According to this invention, the TFT which exhibits the outstanding TFT performance, the oxide semiconductor film which can be used for the said TFT, the sputtering target which can form the said oxide semiconductor film, and the oxide sintered compact which is the material can be provided.

1 is an X-ray diffraction pattern of the oxide sintered body prepared in Example 1. FIG.
2 is an X-ray diffraction pattern of the oxide sintered body prepared in Example 2. FIG.
3 is an X-ray diffraction pattern of the oxide sintered body prepared in Example 3. FIG.
4 is an X-ray diffraction pattern of the oxide sintered body prepared in Comparative Example 1. FIG.
5 is an X-ray diffraction pattern of the oxide sintered body prepared in Comparative Example 2.
6 is a diagram showing an embodiment of a TFT of the present invention.
Fig. 7 is a diagram showing an embodiment of a TFT of the present invention.

Hereinafter, in this specification, the term "A-B" regarding numerical description means "A or more and B or less."

A 1st aspect of the oxide sintered compact of this invention contains the oxide containing element In, Zn element, Sn element, and Y element, The sintered compact density is 100.00 % or more of theoretical density.

The 1st aspect of the oxide sintered compact of this invention, the 2nd aspect of the oxide sintered compact of this invention mentioned later, and the 3rd aspect of the oxide sintered compact of this invention mentioned later are collectively called the oxide sintered compact of this invention.

Here, "the density of the sintered body is 100.00% or more of the theoretical density" means that the value obtained by dividing the measured density of the oxide sintered body measured by the Archimedes method by the theoretical density of the oxide sintered body is 100.00% or more as a percentage. In the present invention, the theoretical density is calculated as follows.

Theoretical density = total weight of raw material powder used for oxide sintered compact / total volume of raw material powder used for oxide sintered compact

For example, in the case of using oxide A, oxide B, oxide C, and oxide D as the raw material powder of the oxide sintered body, the usage amount (injection amount) of oxide A, oxide B, oxide C, and oxide D is each a (g), When b(g), c(g), and d(g) are set, the theoretical density is computable by applying as follows.

Theoretical density=(a+b+c+d)/((a/density of oxide A)+(b/density of oxide B)+(c/density of oxide C)+(d/density of oxide D))

In addition, since the density of each oxide is almost equal to the density and specific gravity, the specific gravity value of the oxide described in the Basic Edition of the Chemical Handbook I Japanese Chemistry Edition 2nd Edition (Maruzen Co., Ltd.) was used.

When the density of the sintered compact of the first aspect of the oxide sintered compact of the present invention is 100.00% or more of the theoretical density, it means that there are few voids that can be the cause of abnormal discharge or the origin of nodules, and the occurrence of cracks during sputtering is small. Stable sputtering becomes possible.

The sintered compact density is preferably 100.01% or more of the theoretical density, and more preferably 100.1% or more. Although there is no upper limit in particular, it is set as 105 % or less. When it exceeds 105%, a metal component may be contained, and it may take time to optimize sputtering conditions or annealing conditions for semiconductor formation, or it may be necessary to form a semiconductor film after determining the conditions for each target. .

The first aspect of the oxide sintered body of the present invention preferably contains a bixbite phase represented by In ₂ O ₃ and a pyrochlor phase represented by Y ₂ Sn ₂ O ₇ . When the oxide sintered body contains a bixbite phase represented by In ₂ O ₃ and a pyrochlor phase represented by Y ₂ Sn ₂ O ₇ , a bixbite phase represented by In ₂ O ₃ and/or Y ₂ Sn ₂ O ₇ of the zinc element It is dissolved in the pyrochlore phase represented by , and the oxide sintered body can exhibit a high density.

That the oxide sintered body contains the bixbite phase represented by In ₂ O ₃ and the pyrochlor phase represented by Y ₂ Sn ₂ O ₇ can be confirmed by examining the crystal structure with an X-ray diffraction measurement device (XRD).

The 1st aspect of the oxide sintered compact of this invention may also contain Indium Trizincoindate represented by _In (( _Zn3In )O6) in the range which does not impair the effect of this invention.

The crystal phase of the first aspect of the oxide sintered body of the present invention is a bixbite phase represented by In ₂ O ₃ , a pyrochlor phase represented by Y ₂ Sn ₂ O ₇ , and optional In((Zn ₃ In)O ₆ ) It may consist only of the indium trizine coin date phase shown.

In addition, in a sintered body containing indium oxide and zinc oxide, a bixbyite compound composed of indium oxide and a hexagonal layered compound represented by In ₂ O ₃ (ZnO) _m (where m is an integer of 1 to 20) are produced. do. This indicates that the zinc element does not dissolve in indium oxide and reacts with indium oxide. Even if yttrium oxide is added to this composition, a hexagonal layered compound represented by indium oxide and/or In ₂ O ₃ (ZnO) ₂ in which the yttrium element is dissolved is produced.

In the sintered body containing indium oxide, zinc oxide and tin oxide, a bixbite compound usually composed of indium oxide and In ₂ O ₃ (ZnO) _m (where m is an integer of 1 to 20) is a hexagonal layered compound; and a spinel compound represented by Zn ₂ SnO ₄ in some cases.

On the other hand, in the sintered compact containing indium oxide, yttrium oxide, and tin oxide, it is known that the bixbite compound represented by In ₂ O ₃ and the pyrochlor compound represented by Y ₂ Sn ₂ O ₇ appear.

_{In the} oxide sintered compact of this invention, when _it contains the bixbite phase represented by In2O3, it is preferable that the abundance ratio of the bixbite phase represented by In2O3 is 50-99 wt% in an oxide sintered compact, _60-98 It is more preferable that it is wt%.

When the abundance ratio of the bixbite phase represented by In ₂ O ₃ is within the above range, the pyrochlore phase or the indium trizincoindate phase is dispersed in the sintered body containing the bixbite phase represented by In ₂ O ₃ as a main component, and the rare earth element is By doping or the like, application to a fluorescent material other than the target material is also conceivable.

_In the oxide sintered compact of this invention, _it is preferable that the bixbite phase represented by In2O3 is a main component. Thereby, the bulk resistance of a sintered compact is reduced, and it becomes possible to use it suitably as a sputtering target. Moreover, it becomes easy to improve the mobility of the semiconductor thin film obtained from this sputtering target.

"The bixbite phase represented by In ₂ O ₃ is a main component" means that the abundance ratio of the bixbite phase represented by In ₂ O ₃ is 50 wt% or more in the oxide sintered body, preferably 60 wt% or more, more Preferably it is 70 wt% or more, More preferably, it is 80 wt% or more.

When the oxide sintered body of this invention contains the bixbite phase represented by In2O3, it is preferable if any one or more of a Y element and a Zn element are solid _- solution _- substituted in the said bixbite phase. Thereby, it becomes easy to improve the density of a sintered compact.

It can be confirmed that the lattice constant of the bixbite structure of indium oxide in the sintered compact is smaller than the lattice constant of only indium oxide that the zinc element is solid _- solution _- substituted on the bixbite phase represented by In2O3. _In addition, the solid solution substitution of the yttrium element _on the bixbite phase represented by In2O3 can be confirmed by the lattice constant of the bixbite structure of indium oxide in a sintered compact being larger than the lattice constant of only indium oxide.

The solid solution substitution of the zinc element and the yttrium element can be adjusted according to the addition amount of the yttrium oxide used for manufacture of a sintered compact. By making the addition amount of yttrium oxide small, it is possible to produce indium oxide having a bixbite structure substituted with a zinc element in solid solution. can

Here, the "lattice constant" is defined as the length of the lattice axis of the unit lattice, and can be determined by X-ray diffraction method. The lattice constant of the bixbite structure of indium oxide is 10.118 Å.

In the case of a thin film transistor, it is thought that the overlap of orbital becomes large, so that the distance between atoms is short, and it becomes easy to obtain a transistor with high mobility. Therefore, it is considered that the lattice constant of the bixbite structure of indium oxide is smaller than the normal lattice constant of 10.118 angstroms, making it easier to manufacture a high-performance thin film transistor.

As for the 1st aspect of the oxide sintered compact of this invention, Preferably the atomic ratio of Zn, Y, Sn, and In is as follows.

The atomic ratio represented by Zn/(In+Zn+Y+Sn) is preferably 0.01 to 0.25, more preferably 0.03 to 0.25.

The atomic ratio represented by Y/(In+Zn+Y+Sn) is preferably 0.03 to 0.25, more preferably 0.05 to 0.20.

The atomic ratio represented by Sn/(In+Zn+Y+Sn) is preferably 0.03 to 0.30, more preferably 0.05 to 0.30.

The atomic ratio represented by In/(In+Zn+Y+Sn) is preferably 0.20 to 0.93, more preferably 0.25 to 0.87.

By carrying out manufacture of a sintered compact using a raw material so that the said composition may be satisfied, the 1st aspect of the oxide sintered compact of this invention is obtained.

The atomic ratio represented by Zn/(In+Zn+Y+Sn) is preferably 0.01 to 0.25. If it is less than 0.01, the effect of densification by a zinc element is not acquired but only a low-density sintered compact may be obtained. If it exceeds 0.25, the zinc element cannot be dissolved in indium oxide or the pyrochlor compound represented by Y ₂ Sn ₂ O ₇ , and precipitates as zinc oxide or hexagonal layered compounds such as In ₂ O ₃ (ZnO) ₂ appear. There are cases. Moreover, when it exceeds 0.25, when the semiconductor layer of the thin film transistor (TFT) is formed using the sputtering target manufactured from the sintered compact, only the TFT which lacks stability may be obtained.

The atomic ratio represented by Zn/(In+Zn+Y+Sn) is preferably 0.03 to 0.25, more preferably 0.05 to 0.22, still more preferably 0.08 to 0.20.

The atomic ratio represented by Y/(In+Zn+Y+Sn) is preferably 0.03 to 0.25. If it is less than 0.03, when a semiconductor layer of a thin film transistor (TFT) is formed using a sputtering target manufactured from a sintered body, it may not be semiconductorized and may be a conductor, and only a TFT lacking stability may be obtained. Moreover, when it exceeds 0.25 and the semiconductor layer of the thin film transistor (TFT) is formed using the sputtering target manufactured from the sintered compact, it may become insulator without being semiconductorized.

The atomic ratio represented by Y/(In+Zn+Y+Sn) is preferably 0.05 to 0.22, more preferably 0.05 to 0.20, still more preferably 0.07 to 0.20.

The atomic ratio represented by Sn/(In+Zn+Y+Sn) is preferably 0.03 to 0.30. If it is less than 0.03, the resistance value of a target does not fall, or a sintering density does not rise, but the intensity|strength of a sintered compact after that does not rise, or it may exert a bad influence on a linear expansion coefficient and thermal conductivity. In addition, when a semiconductor layer of a thin film transistor (TFT) is formed using a sputtering target manufactured from a sintered body of less than 0.03, it is dissolved in a mixed acid composed of phosphoric acid, nitric acid, and acetic acid, which is an etching solution for wiring metal, and the structure of the TFT It may become impossible to form an in-back channel TFT. On the other hand, when it exceeds 0.30, it becomes easy to improve the density of a sintered compact. Moreover, when the semiconductor layer of a thin film transistor (TFT) is formed using the sputtering target manufactured from the sintered compact, it may become impossible to etch with organic acids, such as oxalic acid, and it may become impossible to form TFT.

The atomic ratio represented by Sn/(In+Zn+Y+Sn) is preferably 0.05 to 0.30, more preferably 0.08 to 0.28, still more preferably 0.10 to 0.25.

The atomic ratio represented by In/(In+Zn+Y+Sn) is preferably 0.20 to 0.93.

The composition ratio of the indium element in the sintered body is preferable because a high-mobility TFT, which is a characteristic of the TFT, can be obtained.

The atomic ratio represented by In/(In+Zn+Y+Sn) is preferably 0.25 to 0.87.

In the oxide sintered compact of this invention, content (atomic ratio) of each metal element in a sintered compact can be calculated|required by measuring the abundance of each element by ICP (Inductively Coupled Plasma) measurement, for example.

The oxide sintered body of the present invention may contain indium element, zinc element, tin element and yttrium element, and the metal element contained in the oxide sintered body of the present invention is substantially composed of indium element, zinc element, tin element and yttrium element. also be

In the present invention, "substantially" means that the content ratio of the indium element, zinc element, tin element and yttrium element in the metal element contained in the oxide sintered body is, for example, 90 atm% or more, 95 atm% or more, 98 atm% It means more than, 99 atm% or more, or 100 atm%.

The oxide sintered compact of this invention may contain a gallium element as metal elements other than an indium element, a zinc element, a tin element, and a yttrium element in the range which does not impair the effect of this invention.

The bulk resistance of the oxide sintered body of the present invention is preferably 10 mΩcm or less, more preferably 8 mΩcm or less, and particularly preferably 5 mΩcm or less. Bulk resistance can be measured by the method described in the Example.

When bulk resistance is large, when forming into a film with large power, there exists a possibility that a target may be electrically charged and generate|occur|produce an abnormal discharge, or a plasma state may not be stable, and there exists a possibility that a spark may generate|occur|produce.

The three-point bending strength of the oxide sintered body of the present invention is preferably 120 MPa or more, more preferably 140 MPa or more, and still more preferably 150 MPa or more.

When the three-point bending strength is small, when sputtering film is formed with a large power, since the strength of the target is weak, there is a fear that the target cracks or causes chipping, and the solid scatters on the target, which may cause abnormal discharge. Three-point bending strength can be evaluated according to JISR1601 "room temperature bending strength test of fine ceramics." Specifically, a standard test piece with a width of 4 mm, a thickness of 3 mm, and a length of 40 mm is used. It can be evaluated by adding and calculating the bending strength from the maximum load at the time of failure.

The coefficient of linear expansion of the oxide sintered body of the present invention is preferably 8.0×10 ^-6 (K ^-1 ) or less, more preferably 7.5×10 ^-6 (K ^-1 ) or less, and 7.0×10 ^-6 (K ^-1 ) or less. ) or less, it is more preferable.

If the coefficient of linear expansion is large, it is heated during sputtering with large power to expand the target, and deformation occurs between the copper plate and the bonded copper plate. there is a risk of becoming

The coefficient of linear expansion is, for example, using a standard test piece having a width of 5 mm, a thickness of 5 mm, and a length of 10 mm, setting the temperature increase rate to 5 ° C / min, and positioning the displacement due to thermal expansion when 300 ° C is reached It can be evaluated by using a detector.

The thermal conductivity of the oxide sintered body of the present invention is preferably 5.0 (W/m·K) or more, more preferably 5.5 (W/m·K) or more, and still more preferably 6.0 (W/m·K) or more, , 6.5 (W/m·K) or more is most preferable.

When the thermal conductivity is small, in the case of sputtering film formation with a large power, the temperature of the sputtered surface and the bonded surface are different, and there is a possibility that microcracks, cracks, or chipping may occur in the target due to internal stress.

The thermal conductivity can be calculated by, for example, using a standard test piece having a diameter of 10 mm and a thickness of 1 mm, determining the specific heat capacity and the heat diffusivity by the laser flash method, and multiplying this by the density of the test piece.

A second aspect of the oxide sintered body of the present invention contains an In element, a Zn element, a Sn element, and a Y element, the atomic ratio of the Zn element and the In element is in the following range, and does not contain a spinel phase represented by Zn ₂ SnO ₄ does not

0.01≤Zn/(In+Zn+Y+Sn)≤0.25

0.50≤In/(In+Zn+Y+Sn)

Thereby, there are few cracks during the production of the oxide sintered body, there are few cracks in the bonding process of bonding the sputtering target to the backing plate, and the sputtering target with less microcracks when forming a film with large power during sputtering. can be obtained

It can be confirmed that the 2nd aspect of the oxide sintered compact of this invention does not contain the spinel phase represented by _Zn2SnO4 by examining the crystal structure with an X _- ray diffraction measuring apparatus (XRD), for example.

In the second aspect of the oxide sintered body of the present invention, the atomic ratio represented by Zn/(In+Zn+Y+Sn) is preferably 0.03 to 0.25 from the viewpoint of improving the density of the sintered body and controlling the crystallinity of the oxide semiconductor film obtained. , More preferably, it is 0.05-0.22, More preferably, it is 0.08-0.20.

In addition, the atomic ratio represented by In/(In+Zn+Y+Sn) is preferably 0.50 to 0.93, more preferably 0.50 to 0.87 from the viewpoint of improving the density of the sintered body and maintaining high mobility of the resulting TFT. .

It is preferable that the _2nd aspect of the oxide sintered compact of this invention contains the bixbite phase represented by _In2O3 , _{and the} pyrochlore phase represented by _Y2Sn2O7 .

Thereby, a zinc element is dissolved in _the bixbite phase represented by _In2O3 and/or _the pyrochlore phase represented by _Y2Sn2O7 , and an oxide sintered compact can show _high density.

The oxide sintered body containing the bixbite phase represented by In ₂ O ₃ and the pyrochlor phase represented by Y ₂ Sn ₂ O ₇ has, for example, a crystal structure determined by X-ray diffraction measurement (XRD) as described above. It can be confirmed by investigation.

A second aspect of the oxide sintered body of the present invention is from the viewpoint of improving the density of the sintered body, and controlling the crystallinity of the obtained oxide semiconductor film, and from the viewpoint of maintaining the TFT mobility high, the atomic ratio of the Y element and the Sn element It is preferable that it is the following range.

0.03≤Y/(In+Zn+Y+Sn)≤0.25

0.03≤Sn/(In+Zn+Y+Sn)≤0.30

In the second aspect of the oxide sintered body of the present invention, the atomic ratio expressed by Y/(In+Zn+Y+Sn) is from the viewpoint of controlling the compound in the oxide sintered body, and the CVD process in the manufacturing process of the protective film or insulating film of the TFT, and heating thereafter From a viewpoint of maintaining the heat resistance of the oxide semiconductor film in a process, Preferably it is 0.05-0.22, More preferably, it is 0.05-0.20, More preferably, it is 0.07-0.20.

In addition, the atomic ratio represented by Sn/(In+Zn+Y+Sn) is preferably 0.05 to 0.30 from the viewpoint of controlling the compound in the oxide sintered body and improving the resistance to the chemical solution for etching the metal of the obtained oxide semiconductor film. , More preferably, it is 0.08-0.28, More preferably, it is 0.10-0.25.

A third aspect of the oxide sintered body of the present invention contains an In element, a Zn element, a Sn element and a Y element, and satisfies that the atomic ratio of the Zn element and the In element is within the following range;

It consists only of a bixbite phase represented by In ₂ O ₃ and a pyrochlor phase represented by Y ₂ Sn ₂ O ₇ , or

It consists only of the bixbite phase represented by _In2O3 , the pyrochlor phase represented by _Y2Sn2O7 , and the indium _{trizine coindate} phase represented by _In (( _Zn3In ) _O6 ).

0.01≤Zn/(In+Zn+Y+Sn)≤0.25

0.50≤In/(In+Zn+Y+Sn)

Thereby, there are few cracks in the middle of manufacture of an oxide sintered compact, there are few cracks in the bonding process of bonding a sputtering target to a backing plate, The sputtering target with little generation|occurrence|production of microcracks when forming a film with large power during sputtering can be obtained.

A third aspect of the oxide sintered body of the present invention consists only of a bixbite phase represented by In ₂ O ₃ and a pyrochlor phase represented by Y ₂ Sn ₂ O ₇ , or a bixbite phase represented by In ₂ O ₃ ; What consists only of the pyrochlore phase represented by Y ₂ Sn ₂ O ₇ and the indium trizine coinate phase represented by In((Zn ₃ In)O ₆ ) is, for example, the above-described X-ray diffraction measuring apparatus (XRD) can be confirmed by examining the crystal structure by

In the third aspect of the oxide sintered body of the present invention, the atomic ratio represented by Zn/(In+Zn+Y+Sn) is preferably 0.03 to 0.25, from the viewpoint of improving the density of the sintered body and controlling the crystallinity of the oxide semiconductor film obtained, More preferably, it is 0.05-0.22, More preferably, it is 0.08-0.20.

In addition, the atomic ratio represented by In/(In+Zn+Y+Sn) is preferably 0.50 to 0.93, more preferably 0.50 to 0.87, from the viewpoint of improving the density of the sintered body and maintaining high mobility of the TFT obtained.

A third aspect of the oxide sintered body of the present invention is from the viewpoint of improving the density of the sintered body, and controlling the crystallinity of the obtained oxide semiconductor film, and from the viewpoint of maintaining the TFT mobility high, the atomic ratio of the Y element and the Sn element is as follows range is preferred.

0.03≤Y/(In+Zn+Y+Sn)≤0.25

0.03≤Sn/(In+Zn+Y+Sn)≤0.30

In the third aspect of the oxide sintered body of the present invention, the atomic ratio represented by Y/(In+Zn+Y+Sn) is from the viewpoint of controlling the compound in the oxide sintered body, and the CVD process in the TFT protective film or insulating film manufacturing process, and heating thereafter From a viewpoint of maintaining the heat resistance of the oxide semiconductor film in a process, Preferably it is 0.05-0.22, More preferably, it is 0.05-0.20, More preferably, it is 0.07-0.20.

In addition, the atomic ratio represented by Sn/(In+Zn+Y+Sn) is preferably 0.05 to 0.30 from the viewpoint of controlling the compound in the oxide sintered body and improving the resistance to the chemical solution for etching the metal of the obtained oxide semiconductor film. , More preferably, it is 0.08-0.28, More preferably, it is 0.10-0.25.

The oxide sintered body of the present invention passes through a step of preparing a mixed powder of a raw material powder containing an indium element, a zinc element, a tin element and a yttrium element, a step of molding the mixed powder to produce a compact, and a step of firing the compact can be manufactured by

The raw material powder is preferably an oxide powder, and indium oxide, zinc oxide, tin oxide and yttrium oxide are preferably used as the raw material powder.

The mixing ratio of the raw material powder may correspond to the atomic ratio of the sintered body to be obtained, and in the first aspect of the oxide sintered body of the present invention, it is preferable to mix at a mixing ratio satisfying the following atomic ratio:

0.01≤Zn/(In+Zn+Y+Sn)≤0.25

0.03≤Y/(In+Zn+Y+Sn)≤0.25

0.03≤Sn/(In+Zn+Y+Sn)≤0.30

0.20≤In/(In+Zn+Y+Sn)≤0.93

Further, in the second and third aspects of the oxide sintered body of the present invention, it is preferable to mix in a mixing ratio that satisfies the following atomic ratios:

0.01≤Zn/(In+Zn+Y+Sn)≤0.25

0.50≤In/(In+Zn+Y+Sn)

A more preferable mixing ratio, etc. with respect to the said mixing ratio is the same as the atomic ratio demonstrated for the oxide sintered compact of each aspect.

The average particle diameter of the raw material powder is preferably 0.1 µm to 2 µm, and more preferably 0.5 µm to 1.5 µm. The average particle diameter of the raw material powder can be measured with a laser diffraction type particle size distribution device or the like.

The mixing and shaping|molding method of a raw material are not specifically limited, A well-known method can be used and implemented. In addition, when mixing, you may add a binder.

Mixing of raw materials can be performed using well-known apparatuses, such as a ball mill, a bead mill, a jet mill, or an ultrasonic apparatus, for example. Although conditions, such as grinding|pulverization time, just need to adjust suitably, about 6 to 100 hours are preferable. The molding method can be, for example, press-molding the mixed powder to obtain a molded article. According to this process, it shape|molds into the shape of a product (for example, a shape suitable as a sputtering target).

A molded object can be obtained by filling mixed powder into a shaping|molding die, and shaping|molding with a metal mold|die press or cold isostatic press (CIP), for example at a pressure of 100 MPa or more normally.

Moreover, at the time of a shaping|molding process, you may use shaping|molding auxiliary agents, such as polyvinyl alcohol, polyethyleneglycol, methyl cellulose, polywax, oleic acid, and a stearic acid.

The obtained molding can be sintered at the sintering temperature of 1200-1650 degreeC for 10 hours or more, and a sintered compact can be obtained.

The sintering temperature is preferably 1350 to 1600°C, more preferably 1400 to 1600°C, still more preferably 1450 to 1600°C. The sintering time is preferably 10 to 50 hours, more preferably 12 to 40 hours, still more preferably 13 to 30 hours.

If the sintering temperature is less than 1200°C or the sintering time is less than 10 hours, since sintering does not proceed sufficiently, the electrical resistance of the target does not sufficiently decrease, which may cause abnormal discharge. On the other hand, when the sintering temperature exceeds 1650°C or the sintering time exceeds 50 hours, significant crystal grain growth causes an increase in average grain size and generation of coarse voids, resulting in a decrease in the strength of the sintered body. There is a risk of causing one or more discharges.

In the atmospheric pressure sintering method, the compact is sintered (sintered) in an atmospheric atmosphere or an oxygen gas atmosphere. The oxygen gas atmosphere is preferably an atmosphere having an oxygen concentration of, for example, 10 to 50% by volume. In the oxide sintered compact of the present invention, the density of the sintered compact can be increased even when the temperature raising process and the maintaining process (sintering process) are performed in an atmospheric atmosphere.

In addition, it is preferable that the temperature increase rate at the time of sintering sets it as 0.1-2 degree-C/min from 800 degreeC to the sintering temperature (1200-1650 degreeC).

In the sintered body of the present invention, the temperature range from 800 ° C. is the range in which sintering proceeds best. When the temperature increase rate in this temperature range becomes slower than 0.1 degreeC/min, crystal grain growth becomes remarkable and there exists a possibility that densification may not be achieved. On the other hand, when the temperature increase rate is higher than 2°C/min, a temperature distribution occurs in the molded body, and there is a risk that the sintered body may be bent or cracked.

The temperature increase rate in the sintering temperature from 800°C is preferably 0.5 to 2.0°C/min, more preferably 1.0 to 1.8°C/min.

The sputtering target of this invention is obtained by carrying out the cutting and grinding|polishing process of the obtained sintered compact and bonding to a backing plate.

The surface of the sintered body often has a sintered portion in a highly oxidized state or has an uneven surface, and needs to be cut to a specified size. In order to suppress the generation|occurrence|production of abnormal discharge and particle|grains during sputtering, you may perform grinding|polishing of the surface #200 times, or #400 times, and also #800 times. As a bonding method, it is preferable to join by metal indium.

The sputtering target of this invention is applicable to a DC sputtering method, an RF sputtering method, an AC sputtering method, a pulse DC sputtering method, etc.

An oxide semiconductor film can be obtained by film-forming using the said sputtering target.

An oxide semiconductor film can be manufactured by a vapor deposition method, a sputtering method, an ion plating method, a pulse laser vapor deposition method, etc. using the said target.

The oxide semiconductor film of the present invention has the following atomic ratios.

0.01≤Zn/(In+Zn+Y+Sn)≤0.25

0.03≤Y/(In+Zn+Y+Sn)≤0.25

0.03≤Sn/(In+Zn+Y+Sn)≤0.30

0.20≤In/(In+Zn+Y+Sn)≤0.93

When the atomic ratio expressed by Zn/(In+Zn+Y+Sn) is less than 0.01, the oxide semiconductor film is crystallized to form an interface with large crystal grains, and the mobility may become small when used as a TFT. If it exceeds 0.25, the etching rate of an oxide semiconductor film becomes large too much, an etching rate becomes impossible to control, or the chemical-resistance with respect to the stripper of a resist may fall, and the surface of an oxide semiconductor film may melt|dissolve. Moreover, when it exceeds 0.25, when the semiconductor layer of the thin film transistor (TFT) is formed using the sputtering target manufactured from the sintered compact, only the TFT which lacks stability may be obtained.

The atomic ratio represented by Zn/(In+Zn+Y+Sn) is preferably 0.03 to 0.25, more preferably 0.05 to 0.22, still more preferably 0.08 to 0.20.

If the atomic ratio expressed by Y/(In+Zn+Y+Sn) is less than 0.03, it may not be semiconductorized and may be a conductor, and only a TFT lacking stability may be obtained. Moreover, in the case of more than 0.25, it may become insulator without being semiconductorized.

The atomic ratio represented by Y/(In+Zn+Y+Sn) is preferably 0.05 to 0.22, more preferably 0.05 to 0.20, still more preferably 0.07 to 0.20.

If the atomic ratio represented by Sn/(In+Zn+Y+Sn) is less than 0.03, it is dissolved in a mixed acid composed of phosphoric acid, nitric acid, and acetic acid which is an etchant for wiring metal, and the back channel TFT as a structure of the TFT cannot be formed in some cases. On the other hand, when it exceeds 0.30, it may become impossible to etch with organic acids, such as oxalic acid, and it may become impossible to form TFT.

The atomic ratio represented by Sn/(In+Zn+Y+Sn) is preferably 0.05 to 0.30, more preferably 0.08 to 0.28, still more preferably 0.10 to 0.25.

The atomic ratio represented by In/(In+Zn+Y+Sn) is 0.20 to 0.93.

The composition ratio of the indium element in the oxide semiconductor film is preferable because a high mobility TFT characteristic of the TFT is obtained.

The atomic ratio represented by In/(In+Zn+Y+Sn) is preferably 0.25 to 0.87, more preferably 0.50 to 0.87.

The oxide semiconductor film of this invention WHEREIN: Content (atomic ratio) of each metal element in an oxide semiconductor film can be calculated|required by measuring the abundance of each element by ICP (Inductively Coupled Plasma) measurement, for example.

The oxide semiconductor film of the present invention may be amorphous.

The oxide semiconductor film of this invention can be manufactured using the sputtering target of this invention. In that case, although there exist an RF sputtering method, a DC sputtering method, an ion plating method, etc., it is preferable to form into a film by the DC sputtering method.

The oxide thin film obtained from the sputtering target of this invention, such as the said oxide semiconductor film, can be used for TFT, and can be used especially suitably as a channel layer. The element structure of TFT is not specifically limited, A well-known various element structure is employable.

An example of the TFT of this invention is shown in FIG. In this TFT, the semiconductor film 40 which is the oxide semiconductor of this invention is formed in the gate insulating film 30 on the silicon wafer (gate electrode) 20, and the interlayer insulating films 70 and 70a are formed. Reference numeral 70a on the semiconductor film 40 also serves as a channel layer protective layer. A source electrode 50 and a drain electrode 60 are formed on the semiconductor film.

An example of the TFT of this invention is shown in FIG. In this TFT, the semiconductor film 40 which is the oxide semiconductor of this invention is formed in the gate insulating film (for example, SiO2) 30 _on the silicon wafer (gate electrode) 20, and the semiconductor film 40 A source electrode 50 and a drain electrode 60 are formed thereon, and a protective layer 70b (eg, CVD-formed SiO ₂ ) is formed on the semiconductor film 40 , the source electrode 50 and the drain electrode 60 . membrane) is formed.

The silicon wafer 20 and the gate insulating film 30 may use a silicon wafer with a thermal oxide film, use a silicon wafer as a gate electrode, and make a thermal oxide film (SiO2) _a gate insulating film.

In addition, in FIG.6 and FIG.7, you may form the gate electrode 20 on board|substrates, such as glass.

It is preferable that the oxide semiconductor film of this invention has a band gap of 3.0 eV or more. When the band gap is 3.0 eV or more, the light on the long wavelength side is not absorbed from the wavelength vicinity of 420 nm. Thereby, when light from the light source of organic EL or TFT-LCD is not absorbed, and when it uses as a channel layer of TFT, there is no malfunction by light of TFT, etc., and optical stability can be improved. Preferably it is 3.1 eV or more, More preferably, it is 3.3 eV or more.

In the TFT of the present invention, the material for forming the respective electrodes of the drain electrode, the source electrode and the gate electrode is not particularly limited, and a material generally used can be arbitrarily selected. For example, transparent electrodes such as indium tin oxide (ITO), indium zinc oxide (IZO), ZnO, SnO ₂ , Al, Ag, Cu, Cr, Ni, Mo, Au, Ti, metal electrodes such as Ta, Alternatively, a metal electrode or a laminate electrode of an alloy containing these can be used. In addition, a silicon wafer may be used as a board|substrate, and in that case, a silicon wafer also acts as an electrode.

In the TFT of the present invention, the material for forming the insulating film and the protective film is not particularly limited, and a material generally used can be arbitrarily selected. Specifically, for example, SiO ₂ , SiN _x , Al ₂ O ₃ , Ta ₂ O ₅ , TiO ₂ , MgO, ZrO ₂ , CeO ₂ , K ₂ O, Li ₂ O, Na ₂ O, Rb ₂ O, A compound such as Sc ₂ O ₃ , Y ₂ O ₃ , HfO ₂ , CaHfO ₃ , PbTiO ₃ , BaTa ₂ O ₆ , SrTiO ₃ , Sm ₂ O ₃ , or AlN may be used.

In the TFT of the present invention, in the case of a back channel etch type (bottom gate type) TFT, it is preferable to form a protective film on the drain electrode, the source electrode and the channel layer. By forming a protective film, even when it drives TFT for a long time, durability becomes easy to improve. Moreover, in the case of a top gate type TFT, it becomes the structure in which the gate insulating film was formed on the channel layer, for example.

A protective film or an insulating film can be formed, for example by CVD, However, in that case, it may become a process by high temperature. Further, the protective film or the insulating film often contains an impurity gas immediately after the film formation, so it is preferable to heat treatment (anneal treatment). By removing these impurity gases by heat treatment, it becomes a stable protective film or insulating film, and it becomes easy to form a TFT element with high durability.

By using the oxide semiconductor film of the present invention, the effect of temperature in the CVD process and the subsequent heat treatment are less affected, so even when a protective film or an insulating film is formed, the stability of the TFT characteristics can be improved. there is.

Example

Hereinafter, this invention is demonstrated using an Example and a comparative example. However, the present invention is not limited to these Examples.

Examples 1 to 9

Zinc oxide powder, yttrium oxide powder, tin oxide powder and indium oxide powder were weighed so that the atomic ratios shown in Table 1 (Table 1-1 and Table 1-2 are collectively referred to as Table 1), and put into a polyethylene pot , mixed and pulverized by a dry ball mill for 72 hours to prepare a mixed powder.

This mixed powder was put into a mold, and the pressure of 500 kg/cm<2> was made into the press-formed body. The compact was densified by CIP at a pressure of 2000 kg/cm 2 . Next, this molded object was installed in a kiln, and after holding at 350 degreeC for 3 hours in atmospheric pressure atmosphere, it heated up at 100 degreeC/hour and sintered at 1450 degreeC for 20 hours. Thereafter, it was allowed to cool by standing to obtain an oxide sintered body.

The crystal structure of the obtained sintered compact was investigated with the X-ray diffraction measuring apparatus (XRD). The XRD charts of the sintered compacts of Examples 1-3 are shown to FIGS. 1-3, respectively.

As a result of analyzing a chart by _JADE6 , in the sintered compact of Examples 1-9, _the bixbite phase represented by _In2O3 and _the pyrochlore phase represented by _Y2Sn2O7 were confirmed. In the sintered body of Examples 2 to 4, 6, 8, and 9, an Indium Trizincoindate phase represented by In((Zn ₃ In)O ₆ ) was also confirmed.

In Examples 1 and 2, the lattice constants of the bixbite structure represented by In ₂ O ₃ are 10.06889 Å and 10.09902 Å, respectively, and therefore, in Examples 1 and 2, the zinc element is solid-solution substitution on the bixbyite phase represented by In ₂ O ₃ in Examples 1 and 2 It can be seen that it has been In Example 3, since the lattice constant of the bixbite structure represented by In ₂ O ₃ is 10.13330 Å, it can be seen that in Example 3, the yttrium element is solid-dissolved on the bixbite represented by In ₂ O ₃ .

In addition, the measurement conditions of XRD are as follows. The lattice constant was determined from the obtained X-ray diffraction.

Apparatus: Smartlab manufactured by Rigak Co., Ltd. X-ray: Cu-Kα ray (wavelength 1.5418 Å, monochrome with graphite monochromator)

2θ-θ reflection method, continuous scan (2.0°/min)

Sampling Interval: 0.02°

Slit DS (diverging slit), SS (scattering slit), RS (receiving slit): 1 mm

The following evaluation was performed about the sintered compact obtained in Examples 1-9. A result is shown in Table 1.

(1) Elemental composition ratio (atomic ratio)

The element composition in the sintered body was measured by an induction plasma emission spectrometer (ICP-AES).

(2) Lattice constants of the bixbyte structure

The lattice constant of the bixbite structure was confirmed from the result of XRD used to confirm the crystal structure.

(3) relative density

The relative density was calculated by measuring the measured density of the produced oxide sintered compact by the Archimedes method, and dividing the measured density by the calculated density of the oxide sintered compact. The calculated density was computed by dividing the total weight of the raw material powder used for manufacture of the oxide sintered compact by the total volume of the raw material powder used for manufacture of the oxide sintered compact.

(4) Bulk resistance

The bulk resistance (conductivity) of the sintered body was measured based on the four-probe method using a resistivity meter (manufactured by Mitsubishi Chemical Co., Ltd., Loresta AX MCP-T370).

(5) the ratio of abundance of each crystal phase

The abundance ratio (wt%) of each crystal phase in the obtained sintered compact was calculated|required by the abundance ratio by the whole pattern fitting (WPF) method from an XRD chart.

[Table 1-1]

[Table 1-2]

Comparative Examples 1 to 4

In the same manner as in Examples 1 to 9, except that yttrium oxide powder, tin oxide powder, indium oxide powder, and zinc oxide powder were used so that the atomic ratios shown in Table 2 were (Comparative Examples 1 and 2 did not use zinc oxide powder) A sintered body was prepared and evaluated. A result is shown in Table 2.

[Table 2]

Examples 10, 11, 14, 15, 16

<Manufacture of thin film transistor (TFT)>

(1) film forming process

The sputtering target was produced using the sintered compact shown in Table 3 obtained in Examples 2, 3, 1, 6, 7. On a silicon wafer (gate electrode) provided with a thermal oxide film (gate insulating film), a 50 nm thin film (semiconductor film) was formed by sputtering through a metal mask using these sputtering targets. A mixed gas of high-purity argon and high-purity oxygen was used as the sputtering gas. A result is shown in Table 3.

(2) Formation of source/drain electrodes

As the source/drain electrodes, a titanium metal was sputtered and formed using a metal mask. The obtained laminate was heat-processed at 350 degreeC for 30 minutes in air|atmosphere, and TFT was completed.

(3) Formation of a protective insulating film

In the TFT obtained in (2), on the semiconductor film after heat treatment, a SiO ₂ film (protective insulating film) is formed by chemical vapor deposition (CVD) at a substrate temperature of 350° C., and then 350 as a post-annealing method Heat treatment was performed at 30°C.

<Semiconductor film production and characteristic evaluation>

· atomic ratio

The element composition in the semiconductor film was measured by an induction plasma emission analyzer (ICP-AES). A result is shown in Table 3.

· Hall effect measurement

The sample which mounted only the semiconductor film on the glass substrate was formed into a film, the hole measurement was performed in each step of the said TFT manufacture, and the increase/decrease of carrier density was measured. Specifically, it is as follows. A result is shown in Table 3.

In the same manner as in the TFT manufacturing process, a semiconductor film with a thickness of 50 nm is formed on a glass substrate, heat-treated at 350° C. for 30 minutes, and then cut into a 1 cm square, and gold (Au) is placed at the 4 corners by 2 mm × A film was formed with an ion coater using a metal mask to have a size of 2 mm or less, and indium solder was placed on the Au metal and contact was made to obtain a Hall effect measurement sample.

ABC-G manufactured by Nippon Denki Glass Co., Ltd. was used for the glass substrate.

The sample for Hall effect measurement was set in a Hall effect/resistance measuring apparatus (ResiTest8300 type, manufactured by Toyo Technica), Hall effect was evaluated at room temperature, and carrier density and mobility were calculated|required.

After forming a SiO ₂ film on the semiconductor film of the sample for Hall effect measurement by a CVD apparatus at a substrate temperature of 350°C, Hall measurement was performed. Further, Hall measurement was also performed after heat treatment at 350°C for 30 minutes. A contact was made by piercing the SiO ₂ film with a measuring needle to the layer of gold.

· Crystalline properties of semiconductor films

The crystallinity of the unheated film after sputtering (after film deposition) and the film after heating was evaluated by X-ray diffraction (XRD) measurement. As a result, it was amorphous before heating, and it was amorphous after heating.

· Band gap of semiconductor film

Transmittance spectrum of a thin film sample formed by sputtering using a sputtering target prepared from the sintered body shown in Table 3 of Examples 2, 3, 1, 6, and 7 and heat-treated at 350° C. for 30 minutes was measured. After converting the wavelength on the horizontal axis into energy (eV), and the transmittance on the vertical axis into (αhν) ² (where α is the absorption coefficient, h is the Planck’s constant, and ν is the frequency), it is fitted to the part where the absorption rises. , the eV value at the point where it intersects the baseline was calculated.

<Characteristic evaluation of TFT>

The following characteristics of the TFT obtained in the above (2) and the TFT in which the SiO ₂ protective film was formed in the above (3) were evaluated. About the TFT obtained in ( ₃ ), the SiO2 film|membrane was evaluated by piercing the needle for a measurement to the layer of metallic titanium. A result is shown in Table 3.

· Saturation mobility

The saturation mobility was calculated|required from the transfer characteristic when 5V was applied to a drain voltage. Specifically, a graph of the transfer characteristic Id-Vg was created, the transconductance (Gm) of each Vg was calculated, and the saturation mobility was derived by the equation of the linear region. In addition, Gm is expressed by ∂(Id)/∂(Vg), and Vg is applied up to -15 to 25 V, and the maximum mobility in the range was defined as the saturation mobility. In the present invention, unless otherwise specified, saturation mobility was evaluated by this method. Id is the current between the source and drain electrodes, and Vg is the gate voltage when the voltage Vd is applied between the source and drain electrodes.

· Threshold voltage

The threshold voltage (Vth) was defined as Vg at Id=10 ⁻⁹ A from the graph of the transfer characteristic.

· on-off ratio

The ratio [On/Off] was determined by setting the Id value of Vg = -10 V as the Off current value and the Id value of Vg = 20 V as the On current value.

[Table 3]

Examples 12, 13, Comparative Example 5

Sputtering targets were produced using the sintered bodies obtained in Examples 2 and 3 and Comparative Example 1. The durability test was done as follows about a sputtering target.

Under the sputtering conditions for forming a semiconductor film shown in Table 3, the DC film-forming power was 400 W, and the target surface after performing operation for 10 hours continuously was observed. In the target surface using the sintered compact of Examples 2 and 3, a large change was not seen other than generation|occurrence|production of an erosion. On the other hand, in the target using the sintered compact of Comparative Example 1, many black foreign substances were seen in the erosion part. In addition, hairline cracks were observed. Moreover, when the frequency|count of abnormal discharge was measured with a micro-arc counter, in the target using the sintered compact of Examples 2 and 3, although almost no arc was measured, in the target using the sintered compact of Comparative Example 1, it occurred frequently.

When firing under an atmospheric atmosphere, the density of the sintered body is less likely to increase than with techniques using HIP, discharge plasma sintering (SPS), or an oxygen atmosphere firing furnace. However, as shown in Table 1, it can be seen that the sintered compact of the example of the present application has a high density even when it is fired in a simple atmospheric atmosphere. Moreover, the oxide semiconductor film which has a composition shown in Table 3 is useful as a thin film transistor.

Industrial Applicability

The sintered compact of this invention can be used as a sputtering target, When the sputtering target obtained can manufacture the oxide semiconductor thin film of a thin film transistor by vacuum processes, such as a sputtering method, it can be used.

Although embodiments and/or examples of the present invention have been described in some detail above, those skilled in the art may add many changes to these illustrative embodiments and/or examples without substantially departing from the novel teachings and effects of the present invention. it is easy to do Accordingly, many variations thereof are included within the scope of the present invention.

All the content of the Japanese application specification used as the basis of the Paris priority of this application is used here.

Claims (15)

contains an oxide containing an In element, a Zn element, a Sn element, and a Y element;
The atomic ratios of the In element, the Zn element, the Sn element, and the Y element are in the following ranges,
The abundance ratio of the bixbite phase represented by In ₂ O ₃ is 50 to 99 wt% in the oxide sintered body,
_Furthermore , the oxide sintered compact characterized by containing _the pyrochlore phase represented by _Y2Sn2O7 .
0.01≤Zn/(In+Zn+Y+Sn)≤0.25
0.05<Y/(In+Zn+Y+Sn)≤0.25
0.03≤Sn/(In+Zn+Y+Sn)≤0.30
0.53≤In/(In+Zn+Y+Sn)<0.91 delete The method of claim 1,
Oxide sintered body, characterized in that at least one of Y element and Zn element is substituted in solid solution on the bixbite. delete An oxide sintered body comprising an In element, a Zn element, a Sn element and a Y element, the atomic ratio of the Zn element and the In element being in the following range, and not containing a spinel phase represented by Zn ₂ SnO ₄ .
0.01≤Zn/(In+Zn+Y+Sn)≤0.25
0.50≤In/(In+Zn+Y+Sn) 6. The method of claim 5,
An oxide sintered body comprising a bixbite phase represented by In ₂ O ₃ and a pyrochlor phase represented by Y ₂ Sn ₂ O ₇ . 7. The method of claim 6,
Oxide sintered body, characterized in that at least one of Y element and Zn element is substituted in solid solution on the bixbite. 8. The method according to any one of claims 5 to 7,
An oxide sintered body, characterized in that the atomic ratio of the Y element and the Sn element is in the following range.
0.03≤Y/(In+Zn+Y+Sn)≤0.25
0.03≤Sn/(In+Zn+Y+Sn)≤0.30 contains In element, Zn element, Sn element and Y element, and the atomic ratio of the Zn element and In element is within the following range;
It consists only of a bixbite phase represented by In ₂ O ₃ and a pyrochlor phase represented by Y ₂ Sn ₂ O ₇ , or
An oxide sintered body comprising only a bixbite phase represented by In ₂ O ₃ , a pyrochlor phase represented by Y ₂ Sn ₂ O ₇ , and an indium trizine coindate phase represented by In((Zn ₃ In)O ₆ ) .
0.01≤Zn/(In+Zn+Y+Sn)≤0.25
0.50≤In/(In+Zn+Y+Sn) 10. The method of claim 9,
Oxide sintered body, characterized in that at least one of Y element and Zn element is substituted in solid solution on the bixbite. 11. The method according to claim 9 or 10,
An oxide sintered body, characterized in that the atomic ratio of the Y element and the Sn element is in the following range.
0.03≤Y/(In+Zn+Y+Sn)≤0.25
0.03≤Sn/(In+Zn+Y+Sn)≤0.30 The sputtering target characterized by containing the oxide sintered compact in any one of Claims 1, 3, 5, 6, 7, 9, or 10. It is obtained by sputtering the sputtering target according to claim 12,
An oxide semiconductor film characterized in that the atomic ratio of the Zn element, the Y element, the Sn element, and the In element is in the following range.
0.01≤Zn/(In+Zn+Y+Sn)≤0.25
0.05<Y/(In+Zn+Y+Sn)≤0.25
0.03≤Sn/(In+Zn+Y+Sn)≤0.30
0.53≤In/(In+Zn+Y+Sn)<0.91 14. The method of claim 13,
An oxide semiconductor film characterized in that it is amorphous. A thin film transistor comprising the oxide semiconductor film according to claim 13 .

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